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DIY: Do It Yourself Post here to share or improve your wrench turning skills! All BMW E46 DIY tips, tales, and projects discussed inside. Learn to work on your car and know the right BMW parts you will need!

All M52TUs have it, really annoying and causes jerky or slow shifts. Dealer wanted to charge me to diagnose it, about $100 for parts, money for installation, and more. I said F that, I'm gonna fix it myself.

Alright, so i wanted to ground the switch to fix it.

I took out all the covers and and the metal plate to expose everything. You then need to unplug the yellow harness

Notice the car won't start now. The harness has 3 wires, one power wire and 2 grounds. One of the grounds is to start the car and the other for changing gears while driving. You want to ground the starting ground.

So with a multimeter, I figured out which one is the one to start the car, and crimped both wires together. You're just connecting these 2 wires together to ground it and make it "always on"

After you connect the wires together, make sure everything is nice and tight.

DO NOT plug the harness back in, just leave it out.

It'll look like this

Start the car to make sure everything works. Then put everything back together.

Now go for a test drive, you will notice your RPM doesn't hang when you hit the clutch, it goes down right away. Now the ride will be nice and smooth.

Wow dude, thanks for this! This "issue" has always bugged me in the 323i. I'll try this out.

Only question - after this mod, the car will start with the clutch out, right? Also the cruise control will not kick out when the clutch is depressed? If both these conditions are true, it is worth adding a "at your own risk" due to the safety issues with disabling those safety features.

Wow dude, thanks for this! This "issue" has always bugged me in the 323i. I'll try this out.

Only question - after this mod, the car will start with the clutch out, right? Also the cruise control will not kick out when the clutch is depressed? If both these conditions are true, it is worth adding a "at your own risk" due to the safety issues with disabling those safety features.

Mark

I never thought about the cruise control, I'll try it next time I drive it.

I added at the end the car will start without pressing the clutch pedal, it's a safety warning and excitment to others.

I drove the car this morning for a while, put a HUGE smile on my face. MUCH smoother.

Just so I have it straight, is it the switch at the bottom of the clutch travel? Neither of my connectors are yellow...

Mark

Mine was to the left and under the clutch pedal. There was the actual clutch switch which is on the top right of the pedal, that's not it. There was another mechanism on the bottom left with yellow harnesses, that's what I used.

I'll have to check my car out to see if this is why I can't seem to get a clean 1-2 shift for the life of me (no CDV that I can find - checked for that already). Stupid question though - why not pull the pin/wire that is used for the gear changing behavior out of the connector and plug the connector back in, leaving the clutch hall effect switch in the loop for starting only (safety feature, right?) If the pin isn't in the connector it won't get triggered on clutch depression for gear changes. Seems less invasive to me.

i would like this just for the fact that i can start it with out getting in the car now.....but as much as i dismantle my bimmer and put it back together im a lil hesitant to cut some wires hmm....ill probably do it ne way

Stupid question though - why not pull the pin/wire that is used for the gear changing behavior out of the connector and plug the connector back in, leaving the clutch hall effect switch in the loop for starting only (safety feature, right?) If the pin isn't in the connector it won't get triggered on clutch depression for gear changes. Seems less invasive to me.

Scott

Actually it's a good question, but I don't believe there are two separate switches. The three wires should be for + and - power to the hall switch, then a third wire for the output to the ECU. It would be only one switch that you are bypassing which does both functions.

Actually it's a good question, but I don't believe there are two separate switches. The three wires should be for + and - power to the hall switch, then a third wire for the output to the ECU. It would be only one switch that you are bypassing which does both functions.

Mark

It was described above (I haven't bothered to check the TIS to confirm) as a power and 2 grounds to the ECU, one starter interlock and one to inform the ECU of clutch location for engine management during gearchanges. The single hall effect switch would trip both grounds every time the clutch pedal is down. If you don't want the ECU to know the clutch is disengaged just remove the wire from the bundle that transmits that info to the ECU. I'll be checking into this further this week.

Actually it's a good question, but I don't believe there are two separate switches. The three wires should be for + and - power to the hall switch, then a third wire for the output to the ECU. It would be only one switch that you are bypassing which does both functions.

The clutch switch is what gets pressed in by the pedal and the clutch switch module is attached to the master cylinder. Supposedly they are connected in series both have the same pinouts and go to the same locations. This is according to the BMW WDS CD's I have (I can post the picture/documentation if you like)

However on my Clutch switch Module it has a 4th pin but there is no ducumentation to what it does in either my bentley or BMW WDS CD's so I just left it unattached to anything (Maybe thats why I can start my car without depressing the clutch or because I still need it flashed)

But from what I'm reading I'm assuming the 4th pin might be another Ground??

Actually it's a good question, but I don't believe there are two separate switches. The three wires should be for + and - power to the hall switch, then a third wire for the output to the ECU. It would be only one switch that you are bypassing which does both functions.

Mark

Damn, after re-reading I need to clarify this. I meant to say that there aren't two switches within one physical switch module since the three pins are needed to power the hall switch (as Jared details above). Two pins power the switch, and the third provides the output.

Yes, there are two separate switches though - one that engages when the clutch is fully disengaged (out) and another switch that engaes when the clutch is fully engaged (in). My question was which one needs to be bypassed, and apparently it is the first one.

SoundOfSpeed thanks man ..for the back to back dumb questions i had on aim LOL ....but hey man i just did this today and its A LOT better! ....no need for the ECU to tell you how to shift....i reccomend people do this also if the upshift jerks bother you(no ****)

the purple wire was the power wire which might change from the year and make not sure just throwing this tought out there since the colors of my wires were different then those of soundofspeeds

the blue wire was the one that turned on my car

the brown wire was the one that managed the shifting...

again you want the wire that turns your car on and the power one. you're going to be grounding them together with a tap in. One problem I ran into which soundofspeed told me i might run into was that when you squeeze the tap in together it might not cut through the wires enough to make the grounding complete.To fix this I put one wire in the tap-in squeezed it opened the wire and did it for the other one(1.start up wire 2.power wire)then just put both in at the same time ...

it might take a guess and check because i wasn't able to identify which wire was start up wire...i went by the following picture

notice the position of the wires and the harness thats attached to it...the purple one was in the same place as shown...in my case the blue one was where the brown one thats attached to the tap-in is at so i took that as my guess....well it worked for me since it was the start up wire it might or might not work for you...maybe someone could clear this up a bit as to if all of the wires are placed in this order??

speed of sound answered all my stupid questions i had a lot of repetitive ones to make sure i wasn't going to make a mistake that could somehow wreck my car hehe well a lot of you wont have questions or concerns about the process because of his great DIY but if any of you have any questions i'll be more then happy to help